Usually a backlight lighting lamp chain for outdoor use comprises many light emitting modules, such as LED modules. Hence, each LED module must have fine waterproof performance and then can be used in different weathers. To obtain fine waterproof performance, usually with an over molding process or a low pressure molding process and etc., a packaging material is used to encapsulate the LED modules as a whole. However, some electric components (for example, connectors that need not be welded) in the LED modules are much higher than an LED lens and an LED chip. Hence, after encapsulating the LED modules, a part of emitted light will be blocked by the packaging material. To solve this problem, one solution is to increase the size of the LED lens so that the LED lens is high enough, and then during encapsulating the LED modules, the packaging material will not block the light as emitted. However, this must render a overlarge size of the LED lens, and more packaging material will be used during the encapsulating, as a result, the volume of the overall LED modules will increase correspondingly, and the production cost is then higher and the industrial applicability is also lowered due to the large volume.
The prior art discloses another solution. In this solution, a packaging material is used to encapsulate an LED module comprising an LED lens, wherein, grooves surrounding the LED lens are provided in the circumference of the LED lens, which avoids that the light emitted from the LED lens is blocked by the packaging material. This solution can be applied to an LED module having a relatively small LED lens, while its shortcoming is also very obvious that during actual use, water will stay in the grooves for a long time and gradually infiltrates into the LED module. In addition, dust will also gather in the grooves and thus produce negative effects to lighting effect.